Passer rating, turnovers, and scoring
Have rule changes made scoring easier, or interceptions harder?
This season, I was curious how Passer Rating (PR), a stat created by the NFL decades ago to measure passing efficiency, compared to QBR, a stat invented by ESPN that looks at quarterback play beyond PR. The two are intertwined and those who rank high in one tend to rank high in the other.
Of the top 16 quarterbacks in PR, 13 play on teams with winning records, one is on a team with a .500 record, and two play for losing teams. The same holds true for the top 16 in QBR, although a few of the names are different.
I was also curious how PR compares to turnover margin. It turns out that teams that had a higher PR in the game have gone 142-36-1, or have won 79.6% of the games. Teams that have won the turnover battle (which is frequently even) have gone 108-28-1 (79.2%).
The results are virtually identical, and may I suggest that's because each has one huge factor in common: the interception.
Imagine a game where the two quarterbacks have identical stat lines except for interception.
Player A: 30 attempts, 20 completions, 210 yards, 2 touchdowns, 0 interceptions. Passer rating: 109.03
Player B: 30 attempts, 20 completions, 210 yards, 2 touchdowns, 1 interception. Passer rating: 95.14.
If there were no other turnovers in the game, common sense suggests which team probably wins. And, the interception rate also substantially impacts passer rating.
Longtime fans of the NFL may have noticed that there are fewer interceptions than in the past. At the current pace, the typical NFL team will have thrown 13 or 14 interceptions over the 17-game season. Ten years ago they threw 16 in a 16 game season. 20 and 30 years ago, they averaged 17-18 INTs in a 16 game season, 40 years ago they averaged 22-23 in 16 games, and 50 years ago they averaged 21 in a 14-game season.
Lost fumbles are also down. 50 years ago teams lost 1.1 a game; now they lose one every two games. Overall, a team turns over the ball half as often as they did 50 years ago.
Over those 50 years, passing rules have incrementally changed to encourage more passing, and therefore more scoring. And scoring is indeed up; in 1971 teams averaged 19.4 points per game. Today, they average 23, or 3.6 more points.
The increase in scoring, however, might not have been for the expected reasons. Strict rules on defensive holding and pass interference haven't necessarily led to more exciting big pass plays. Instead, the rules have made it more difficult for defenders to intercept the ball.
When an offense has fewer interceptions, it has more drives that end in field goals and touchdowns. Passing touchdowns increased from 1.07 per game in 1970 to 1.57 in 2021. Part of the reason is the increase in passing: attempts went from 25.8 to 34.9, but I think another part is that offenses are picked off far less often.
"Points off turnovers" is an important statistic that tells the story of a game, but the unseen story is the points prevented by turnovers. That can't be quantified as we don't know if a drive would have ended in a field goal, missed field goal, touchdown, or punt.
What we do know is that turnovers are down, and scoring is up.
James Leroy Wilson writes from Nebraska. Follow him on Facebook and Twitter. If you find value in his articles, subscribe and exchange value for value. You may contact him for your writing, editing, and research needs: jamesleroywilson-at-gmail.com.
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